Source: Matcham, Howard. “Sussex Bryophytes: New and Interesting Records.” Sussex Botanical Recording Society Newsletter, no. 59 (January 2005). http://sussexflora.org.uk/wp-content/uploads/2016/03/Newsletter_Jan_2005.pdf.
The end of 2003 had seen the acceptance by the BBS Recorder of Liverworts for a West Sussex record of the Cavernous Crystalwort (Riccia cavernosa). A mud-loving species found growing in the dried up bed of a pond at Maudlin village, east of Chichester. The circumstances of its discovery will be revealed in the forthcoming edition of Sussex Botany (in press) and this chance discovery is the first record for the vice-county. An exceedingly attractive thalloid liverwort with the upper thallus composed of tissue separated by large air chambers giving the appearance of a glistening green sponge. Tens of thousands of coalescing thalli covered the bed of the seasonally dry pond.
Some eighteen months ago I began a field study of Bryum species with the aim of detecting those that possessed and those that did not possess, rhizoidal tubers, (similar to potatoes on Solanum tuberosum roots) a world wide study initiated by Professor Jeff Duckett at QMUL (Queen Mary University of London) with the prospect of a major paper (in prep.) as the end result. During the course of my field work which was to collect species known to possess tubers either frequently or infrequently from a variety of substrata, I gathered the Capillary Thread-moss (Bryum capillare) from the concrete wall of a World War II gun emplacement, north of the windmill at Halnaker Hill.
On looking at the rhizoids under the dissecting microscope I noticed what appeared to be single celled tubers (most tubers consist of several to many cells) on the ends of the ultimate rhizoids. Tubers on B. capillare are infrequent and never single celled. I did not know what these structures represented! On sending the collection to QMUL the answer was most unexpected.
It was a specialized parasitic fungal infection of mosses and a member of the Rozellopsidales (Oomycota, Chromista, better known previously as the Chytridiales in the aquatic phycomycetes) that form zoosporangia in swollen rhizoid cells. These are commonly referred to as “chytrid” galls. They were first described by Peterson (1910), in an unidentified moss from Denmark, who named the fungus Pleotrachelus wildemani and in the Index Fungorum it appears as P. wildemanii. The occurrence of chytrid galls in mosses has only been noticed occasionally in the intervening years. This find from Halnaker Hill is now the subject (with other recent finds from Spain) of a paper entitled: Interactions between parasitic fungi and mosses: pegged and swollen-tipped rhizoids in Funaria and Bryum. (in press) It will be published in the Journal of Bryology in December of this year (2004).
Chytrid fungal infections are decimating frog populations to the point of extinction throughout Australasia and the Americas. The Halnaker Hill collection (unique in not being close to water) and the recent finds in Spain (aquatic) and a very recent find of chytrid galls on the protonema and filimentous axillary gemmae of the Flabby Thread-moss (Bryum laevifilum) that I have found at Swanbourne lake at Arundel are to be the subject of an urgent study by zoologists seeking to find if connections can be made in the life history of this deadly fungus (for the frog) between mosses and amphibians.
Continuing on the subject of tubers in mosses, a recent collection of the Strap-leaved Earth-moss (Ephemerum recurvifolium) from hard packed soil of an artificial earth bank, again at Maudlin village, revealed starch filled tubers on the protonema, not previously seen from this genus. These are currently being cultivated at QMUL.
Relaxing at home during a recent downpour, my wife Louise, remarked, that “the gutters on the shed roof need attention,” waiting for a suitable respite in rainfall I propped a ladder against the offending gutter and climbed up to do as bidden. To my astonishment a moss unfamiliar to me dripped a welcome from a clay roof tile. Rapidly clearing the offending gutter I removed a small portion of the unfamiliar moss and made for the familiar microscope. It then revealed its name, North Grimmia, (Grimmia longirostris) an exceedingly rare species with the next location as far away as North Devon. Not entirely unexpected in Sussex, particularly where the roofs are tiled with clay although the members of this genus are much more familiar in upland Britain. The area around Chichester, however, is unique for southern England in having eight species within a five mile radius of the city!
I enjoy strolling from my home at Strettington along part of the Old Roman road between Chichester and London known as Stane Street. Part of it is now the A285 and another part deviates from the A285 and is now used as a footpath (for centuries past) to the parish of Boxgrove. A moss growing on damp soil, under shade offered by ancient Field Maples (Acer campestre) caught my eye recently and on microscopic examination proved to be the Pretty Nodding-moss (Pohlia lescuriana); it is the first record for the Vice County. This moss is also a member of the Bryales and has recently been transferred from the Bryaceae to the Mniaceae. It also possesses rhizoidal tubers. In this species it is the composition of these tubers that allows for correct identification.
Martínez-Abigar J, Núñez-Olivera, E, Matcham HW, Duckett JG. (2004). Interactions between parasitic fungi and mosses: pegged and swollen-tipped rhizoids in Funaria and Bryum. Journal of Bryology 26 (4): in press.
Petersen HE. (1910). An account of Danish fresh-water phycomycetes, with biological and systematic remarks. Annales Mycologia, Berlin 8: 494-560.